I am pretty sure mine is not a Vacor. I'll try to get a pic. When I saw it though, I immediately thought back to the time Bill posted the huge clay for ID.
I wasn't happy how that ID thread was left. I wasn't sure his was a Vacor to begin with. That was just something I was thinking of. However, if it was a Vacor, my thought was that it was made around the year 2000. That's when the stoney Vacors that I'm familiar with were made. The story which came with Bill's marble suggested that it was older though.
I know that Vacor made clays when they started out in the 1930's. However, I would imagine those looked more like commies than like the recent version. I don't know though.